Download Free Medical The Human Ear and Voice PowerPoint Presentation

The Human Ear and Voice PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Check out this medical presentation on Ear, Nose, and Throat Facts, which is titled "The Human Ear and Voice", to know about the human ear and the process by which sound waves are received and transmitted to the nerve endings that convert mechanical vibrations into electrical impulses.

Tags : Ear, Nose, Throat Facts, Human Ear, Voice

Published on : Jul 10, 2021 | Views : 2303 | Downloads : 0

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

Chapter 6: The Human Ear and Voice The study of the human ear and the process by which sound waves are received and transmitted to the nerve endings that convert mechanical vibrations into electrical impulses. Our study will relate the basic anatomy of the peripheral auditory system to the important features of the place theory of hearing. The frequency and amplitude responses of the ear. Vocal system and the production of speech and musical sounds. Analysis of speech patterns.
Slide 2-

Peripheral Auditory System The human ear is one of the most amazing organs of the body. Possesses an incredible range of sensitivity in frequency and amplitude responses. Frequency response: 20 Hz  20 kHz. A factor of about 1000 or ten octaves Amplitude/Intensity response: Pressure variations of about 1,000,000 to 1. Intensity variations from 10-12 W/m2 – 1 W/m2.
Slide 3-

Peripheral Auditory System Three Parts: Inner ear Middle ear Outer ear
Slide 4-

Function of the Outer Ear
Slide 5-

Eardrum
Slide 6-

Middle Ear Consists primarily of the bone chain of the three ossicles: the hammer, the anvil, and the stirrup. These bones amplify the vibrations coming from the eardrum and transmit to the fluid of the inner ear. Muscles attached to the ossicles help to limit the vibrations of very large-amplitude continuous sounds. Sharp noises such as gunshots or loud music may occur too quickly for the protective mechanism to prevent damage to the middle ear.
Slide 7-

Cochlea
Slide 8-

Oval and Round Window
Slide 9-

The organ of Corti
Slide 10-

Inner Ear and Balance Inside the inner ear are three semicircular canals. Each canal contains tiny hairs, crystals, and fluid. These structures help the canals sense up-and-down, forward and backward, and side-to-side motion. Nerves carry the signals from the canals to the brain.
Slide 11-

Place Theory of Hearing The place theory hearing correlates frequency with location of the response along the basilar membrane.
Slide 12-

Place theory of hearing Place theory of hearing states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane. Therefore, the pitch of a pure tone would be determined by where the membrane vibrates. In technical terms, it states that frequency is encoded according to the tonotopic organization of the neurons. Place theory competes with the rate theory of hearing, which instead states that pitch is signaled by the rate at which the neurons fire.
Slide 13-

Pitch sharpening The relative shortness of the basilar membrane contrasts with the large number of pitches which people can distinguish. Place theory is generally seen as incomplete, lacking a mechanism which would explain our large pitch resolution. Research using modern cochlear implants suggests that the perception of pitch may depend on both the neurons' location and rate at which they fire. http://hyperphysics.phy-astr.gsu.edu/hbase/sound/place.html
Slide 14-

Anatomy of the Ear Sound enters the ear, travels through the auditory canal, and reaches the eardrum. The auditory canal is approximately a tube open at only one end. The other end is closed by the eardrum. A typical length for the auditory canal in an adult is about 3 cm. The speed of sound is 343 m/s. What is the fundamental frequency of the canal? (Interestingly, the fundamental frequency is in the frequency range where human hearing is most sensitive.)
Slide 15-

Amplitude Response of the Ear
Slide 16-

Human Ear and Sensitivity Audible frequency range: 20 Hz – 20,000 Hz Audible intensity range: 10–12 W/m2 - 1 w/m2 10–12 W/m2 = Threshold of hearing 1 W/m2 = Threshold of pain
Slide 17-

Decibels The decibel (dB) is a measurement unit used when comparing two sound intensities. The intensity level b (expressed in decibels) relative to the threshold of hearing, Io is defined as follows:
Slide 18-

ppt slide no 18 content not found
Slide 19-

Periodicity If two or more tones whose frequencies are successive harmonics in some overtone series sounded simultaneously, an additional frequency will be “heard” by most listeners, particularly trained musicians. Periodicity: The neural mechanism of the ear is able to identify the two frequencies as being members of an overtone series and assigns to the total stimulus the fundamental frequency. This is called periodicity pitch, missing fundamental, or subjective fundamental.
Slide 20-

Fundamental Tracking If one plays a sequence of pairs of tones that have frequency ratio 3 to 2 but have different fundamental frequencies, the ear will recognize the periodicity of each pair of notes and supply the fundamental tone for each. This is called fundamental tracking. Eg: 200 and 300 Hz followed by 300 and 450 Hz. Fundamental tracking is used in the production of very-low-frequency organ tones by sounding the 2nd and 3rd harmonics together.